This book is different than its predecessors in that it identifies and synthesizes twelve key constructs that have important implications for both administrators and researchers; these constructs guide administrators engaged in meaningful school improvement efforts and provide researchers an agenda for future study. The articles of the book capture decades of theoretical and research work. Essential Ideas for the Reform of American Schools identifies and synthesizes key constructs that have important implications for the improvement of schools. The articles have been written over a period of several decades and are grounded in theoretical analysis and empirical research. Together they form a coherent body of literature for both practitioners interested in improving schools and researchers committed to the study of school effectiveness. Twelve Key Concepts for School Improvement The chapters are organized around constructs that have been identified as critical aspects of schooling and schools in the United States; all have been published in scholarly national and international journals and all are analyses we have done alone together or with our colleagues and former students. The research and theory demonstrates how a body of work by a group of researchers can build and expand to new areas as old questions are answered and as new ones shape future inquiry.